High temperature titanium alloys, titanium aluminides, nickel aluminides and molybdenum disilicide have all shown promise as composite matrix materials because of their high specific strength at elevated temperatures. However, these materials are subject to "creep" or gradual deformation at high temperatures. Accordingly, they must be reinforced with creep-resistant continuous fibers to be suitable for use at elevated temperatures.
Although the utility of the composites is known, they are difficult to manufacture and expensive. Therefore, there is still a need to provide an economical method for making composites having titanium alloy, titanium aluminide, nickel aluminide or molybdenum disilicide matrices reinforced with high strength continuous ceramic fibers.
As used herein, the term "titanium aluminide" refers to intermetallic compounds wherein titanium and aluminum are present in simple numerical ratios, including Ti.sub.3 Al, TiAl, TiAl.sub.3 and Ti-10Al-26Nb. Some known high temperature titanium alloys are Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo (also known as Ti-6242). All of the alloy compositions mentioned above are described with reference to weight percentages of the alloying elements.
As used herein, the term "nickel aluminide" refers to nickel-aluminum intermetallic compounds and high temperature nickel-aluminum alloys comprising at least one half nickel. The nickel aluminides include NiAl and Ni.sub.3 Al.
It is a principal objective of the present invention to provide a method of forming titanium alloy, titanium aluminide, nickel aluminide and molybdenum disilicide matrix composites reinforced with ceramic fibers, utilizing cast tapes having a powdered matrix.
An additional objective of the invention is to provide a method of making fiber reinforced composite sheet materials.
Some other objectives and advantages of the invention will become apparent to persons skilled in the art from the following detailed description of our invention.